The table shows data from a life cycle assessment of two shopping bags, each used once.
Table: the plastic bag uses 0.6 megajoules and 1.2 grams of raw material from crude oil, releases 0.12 kilograms of carbon dioxide, and lasts a very long time in landfill; the paper bag uses 1.5 megajoules and 50 grams of raw material from trees, releases 0.34 kilograms of carbon dioxide, and biodegrades in weeks.
Measure
Plastic bag
Paper bag
Energy used in MJ
0.6
1.5
Raw material
Crude oil (finite)
Trees (renewable)
Carbon dioxide released in kg
0.12
0.34
After disposal
Lasts many years in landfill
Biodegrades in weeks
Evaluate the environmental impact of the two bags. Use the data in the table.
[6 marks]
6 marksFoundation and Higher
Spec and skills
Original practice question
Answer and supported method checks
A student wants to find out whether a green food colouring contains the same dyes as two known dyes, P and Q.
.1
Describe how the student could use paper chromatography to do this.
[4 marks]
.2
A spot moves 3.9 cm from the start line. The solvent front is 7.8 cm from the start line. Calculate the Rf value.
[2 marks]
6 marksFoundation and Higher
Spec and skills
Original practice question
Answer and supported method checks
Crude oil is separated into fractions in a fractionating column.
Explain how fractional distillation separates crude oil into fractions.
[6 marks]
6 marksFoundation and Higher
Spec and skills
Original practice question
Answer and supported method checks
A student has samples of tap water, sea water and rain water.
Plan an investigation to compare the pH and the mass of dissolved solids in the three samples, and to purify the sea water by distillation.
[6 marks]
3 marksFoundation and Higher
Spec and skills
Original practice question
Answer and supported method checks
When ammonium chloride is heated it decomposes into ammonia and hydrogen chloride. On cooling, they react to form ammonium chloride again.
NH4Cl⇌NH3+HCl
.1
The forward reaction takes in 176 kJ for each mole of ammonium chloride. Give the energy released when one mole of ammonium chloride forms from ammonia and hydrogen chloride.
[1 mark]
.2
Explain why ammonium chloride reforms at the cool top of a test tube when it is heated at the bottom.
